Sequence controller mechanism



July 2, 1963 Filed Sept. 26, 1961 G. D. BROCK ETAL SEQUENCE CONTROLLER MECHANISM 2 Sheets-Sheet 1 July 2, 1963 G. D. BROCK ETAL 3,096,408

SEQUENCE CONTROLLER MECHANISM United States Patent O 3,096,468 SEQUENCE CONTRLLER MECHANISM George D. Brock, Sterling, and Ernest W. Topping, Lyndon, Ill., assignors to General Electric Company, a corporation of New York Filed Sept. 26, 1961, Ser. No. 140,731 Claims. (Cl. 2041-38) This invention relates to sequence controllers, and more particularly to a mechanism for operating a plurality of electric switches in accordance with a predetermined sequence or pattern.

An object of this invention is to provide a novel and improved mechanism for operating a plurality of switches or similar control devices in a predetermined manner.

Another object of this invention is to provide a sequence controller for operating a plurality of electric switches, wherein `an improved manually operable actuating means operates one of the electric switches.

An additional object of this invention :is to provide an improved sequence controller which includes a novel means for positively positioning a rotatable switch actuating unit in a predetermined starting position.

It is a still further object of this invention to provide an improved sequence controller mechanism for electric switches, which mechanism is relatively small in size, compact, and due to its relative simplicity may be manufactured at a reduced cost.

In carrying out the present invention, in one form thereof, there is provided a sequence controller mechanism having a timing motor and a plurality of switches. One of these switches may be a line :switch for controlling the timing motor. To operate these switches in a time driven sequence, a plurality of pivoted followers are distributed ion the periphery of a cylindrically configured rotatable operating unit. The operating unit is intermittently driven by the timing motor, and it includes a plurality of cam members stacked together in coaxial fashion. Each follower is operated by one or more radial interruptions formed in an associated track of one of the cam members, to actuate one of the switches. For setting the switch operating unit, a cam shaft is extended coaxially through the unit. This cam shaft is keyed to the operating unit for manually rotating it, and the shaft is also arranged to reciprocate between two positions relative to the unit. Near an inner end of the cam shaft, there -is formed a frusto-conical camming surface. When the cam shaft is depressed, this conical cammi-ng surface acts upon a V-shaped surface of an actuator to move this actuator transversely relative to the axis of the cam shaft and thereby open the line switch. The line switch may thus be readily turned olf before advancing the rotatable switch operating unit.

For initially positioning the operating unit at a precisely located starting position, a spring biased latching lever is mounted near the line switch actuator at one end of the unit. A positioning notch is formed on a face of the rotatable unit near the lever. The lever has a latching tooth spring biased for movement into engagement with the notch of the unit when the cam shaft is depressed and the unit is thereupon rotated to the desired starting position. With such an arrangement, depression of the cam shaft thus turns oil the line switch before advancement of the switch ioperating unit and at the same time positively positions a stop to insure the commencement of the sequence at a precisely located starting position.

Further aspects of our invention will become apparent hereinafter, and the `specification concludes with claims particularly pointing out and distinctly claiming the subject matter which we regard as our invention. The invention, however, as to organization and method of operation,

3,096,408 Patented July z, 196s ICC together with further objects and advantages thereof, may best be understood by reference to the following description, when taken in conjunction with the accompanying drawings, in which:

FIG. l is a rea-r view of our improved sequence controller with the rear support plate partially broken away to show the manually operated switch actuating arrangement and positive stopping lever;

FIG. 2 is a bottom view of the improved sequence controller partially broken away Aand partially in section along line 2--2 of FIG. l to show some of the cam members and followers operated thereby;

FIG. 3 is a front view of the sequence controller partially broken away to show the `driving mechanism for the switch operating unit and other pertinent structure;

FIG. 4 is a fragmentary perspective view showing the interrelationships of the cam shaft, ratchet wheel, manually operated switch actuator assembly, and positive stopping lever, with the cam shaft being represented in its undepressed or outermost position; and

FIG. 5 is a view similar to FIG. 4, with the cam shaft being represented in its depressed or innermost position.

Referring in detail to the drawings and in particular at first to FIGS. 2-3, there is shown a sequence controller 1 having a suitable timing motor 3, an intermittent drive mechanism 5, a main rotatable switch operating unit 6, and switching mechanisms 7 and 8. Motor 3, as illustrated, is of the self-starting synchronous type, and it transmits rotary motion from output pinion 9 at the desired number `of revolutions per minute for drive mechanism 5 to intermittently rotate switch operating unit 6 )and thereby actuate switching mechanisms 7 and 8.

For supporting and containing the various elements of sequence controller 1 in a compact housing, as shown in FIGS. l and 3, the controller includes a rectangular switch casing 11 formed by front and back plates 13 and 15, respectively, terminal boards 17 and 18, land spacer plates 21. More particularly, the front and back plates 13 and 15 have rectangular slots 23 (shown representatively on front plate 13 in FIG. 3) formed therein near their elongated outer sides. The slots 23 receive and cooperate with mating rectangular bosses 25 projecting edgewise from opposite elongated sides of the terminal boards 17 and 18 (FIG. 3). It will thus be seen that terminal boards 17 and 18 serve structurally as elongated sides for casing 11 (FIG. 3) and help to `space front iand back plates 13 and 15 apart in parallel fashion. For rigid securing the front and back plates 13 and 15 in cooperative engagement with terminal boards 17 and 1S, spacer plates 21 are staked to the outer faces of the front and back plates to secure these parts of the casing together (FIGS. l and 3).

Timing motor 3 is attached to the front side of back plate 15, 4as shown in FIG. 3, by means of screws 27 which extend through appropriate apertures of ears 29 -of the housing 31 of the motor. Screws 27 thread into engagement with apertures (not shown) of the back plate 15 to attach the timing motor thereto. The pinion 9, as shown in FIG. 2, is `disposed rearwardly or on the outer side of back plate 15. A rear support plate 30 is disposed in parallel relationship to back plate 15 and suitably fastened thereto (FIG. 2). Pinion 9 of motor 3 is positioned between plates 15 and 30, as shown in FIG. 2 `and is in mesh with gear 33. Gear 35 is attached to the same shaft as gear 33 and is rotatable therewith. The combination of gears 33 and 35 provides a reduction gearing means for reducing the speed of angular rotation provided by motor pinion 9. Gear 35 meshes with crank gear 37. `Crank gear 37 is attached to a shaft 38 which is journalled at its outer and upper end (FIG. 2) to support plate 30. Auxiliary gear 40 is also attached to shaft 38 and arranged coaxially upon gear 37. The purpose aosenos of auxiliary gear 40 shall be set forth hereinafter. The inner end portion 33* (FIG. 3) of crank gear shaft 38 resembles a crank pin in that it is eccentric to the 'axis of crank gear 37 and `the outer end of shaft 33. The purpose of eccentric `inner end portion 39 of the crank gear shaft 33 shall now be described.

For an understanding of lthe purpose and operation of eccentric inner end portion 39 of the crank shaft 33, attention is drawn to FIG. 3. As shown therein, a locking lever 41 is pivotally mounted on the inner side of back plate 15 by rivet 43. Lever i1 serves a 11o-back function for the intermittent drive mechanism 5. More particularly, the lever 41 includes hooked ear 45 which is connected to an associated hooked end of coiled ten- Sion spring 47, `circular aperture 49 which is larger in diameter than a disc-shaped portion 51 of crank shaft 38 and generally surrounds it, and outer tooth-shaped locking end 53. Between the outer extremity of the eccentric portion 39 and disc portion 51, a driving pawl 55 is rotatably journalled upon eccentric portion 39 (FIG. 3). More particularly, eccentric portion 39 of the crank gear shaft 38 is extended through an appropriate aperture formed in pawl 55, and a C-shaped clip 56 is fitted into engagement with portion 39 to retain the pawl in its proper axial position thereon. Pawl 55 also includes notched arm 57 and tooth-shaped driving end 59. The notched arm 57 is hooked into engagement with one end of tension spring 61.

As further shown in FIG. 3, locking lever spring 47 has its one end attached to hooked ear 45 of lever 41 and the other end attached to lanced tab 63 of back plate 15. Spring 47 runs in tension to continuously bias locking lever 41 in a clockwise direction about rivet 43 (viewing FIG. 3), and thereby urges locking end 53 of the locking lever toward ratchet wheel 65. Spring 61 of the driving pawl 55 has its one end aflixed to notched arm 57 of the pawl 55 and the other end attached to a latching lever which serves an important setting function in the controller. This latching lever and the operation thereof shall be described in detail hereinafter. The spring 61 runs in tension to continuously urge pawl 5S in a clockwise direction about portion 39 (viewing FIG. 3), and thereby biases driving end 59 of the p-awl toward ratchet wheel 65.

Turning now to an explanation of the operation of the intermittent drive mechanism 5 of sequence controller l, it will be seen that when timing motor 3 is energized, it drives pinion 9. Pinion 9 is in continuous mesh with gear 33 (FIG. 2) and thereby `also drives the `attached gear 35. If it is supposed that motor pinion 9 is driving in a counterclockwise direction of rotation from its position as shown in FIG. 3, gears 33 and 35 then will be driven in a clockwise direction of rotation. Gear 35 meshes with crank gear 37 and thus drives it in a counterclockwise direction of rotation. As the crank gear 37 is driven in a counterclockwise direction of rotation, the tooth-shaped driving end 59l of pawl 55 successively enters peripheral notches of ratchet wheel 65 and steps the ratchet wheel 65 in a clockwise direction (viewing FIG. 3). The tooth-shaped locking end 53 of lever 41 serves a no-back function between driving strokes of pawl 55. More particularly, the pawl 55 is driven in a generally sinusoidal fashion to rotate ratchet wheel 65 in a clockwise direction of rotation (viewing FIG. 3), and locking lever 41 engages peripheral notches of the ratchet wheel to intermittently lock the ratchet wheel 65 in the position -to which it has been driven by pawl 55. Pawl 55 and locking lever 4i1 thus act upon ratchet wheel 65 to provide intermittent rotation of the ratchet wheel 65 in one particular direction (i.e., clockwise, viewing FIG. 3).

For controlling the various devices of our improved `sequence controller 1, as shown in FIG. .2, the main rotatable switch operating unit 6 comprises a series of cam members 69 stacked coaxially upon and fastened to ratchet wheel 65. All of the cam members 69 are similar to each other and have a cylindrical bore 71 (FIG. 3) which is centrally located and extends generally perpendicularly between top and bottom ends thereof. The bores 71 surround and receive cam shaft 73 after the various cam members have 'been stacked one upon the other and fastened together in a suitable manner. Each of the cam members 69 includes a pair of frusto-conically stepped annular cam tracks 75 and 77 (FIG. 2) which have radial discontinuities 79 formed thereon. The cam tracks 75 and 77 act upon associated pivoted followers 81 and 33 (FIG. 3) during the intermittent rotation of operating unit '6, to control a plurality of switches.

To provide a means for efficiently actuating the switching devices of the `sequence controller 1 within a relatively small spacial area of the controller housing, -two oppositely disposed groups of the pivoted followers 81 and 83 are utilized. (See FIG. 3.) One of these groups is disposed about `an axis parallel to cam shaft 73 on each side of the main switch operating unit 6. More particularly, shafts and 86 are each suitably positioned through apertures in front plate 13 and back plate 15 on each side of unit 6. These shafts extend outwardly toward support plate 3i) from back plate 15 (as shown in FIG. 5). The followers 81 and 8a3 resemble each other in over-al1 appearance but differ slightly from Ieach other structurally, in that the cam engaging points 81a of followers 81 are thinner in configuration than the cam engaging points 33a of followers 83. The thinner cam engaging points 31a are thus specially adapted to ride upon cam track 75 (FIG. 2), which has a general diameter smaller than the general diameter of cam track 77 (FIG. 2). The cam engaging points 83a ride upon cam tracks 77 (FIG. 2).

Considering further the arrangement of the cam followers 8.1 and 33 on shafts 85 and 86, as shown in FIGS. 2 and 3, the followers are stacked on each shaft in alternate angularly separated disposition, with the shaft extend- Iing through apertures formed in hub portions 81b and 83b of the respective followers. IMore particularly, on each side of the operating unit 6, there is a series of pairs of axially adjacent .followers 81 and 83 which .are angularly spaced with respect to each other. As shown in FIG. 2, it will be -seen that hub portions 81h and -83b for each pair `of axially adjacent followers 81 and 83 cooperate via stepped configurations thereof so that each follower 811 is substantially coplanar to lits associated axially adjacent fol-lower 83. The relatively thick cam engaging poi-nt 83a of follower 83 (FIG. 3) engages cylindrical cam track 77 of an associated cam member 69 `and is actu-ated thereby, and the relatively thin cam engaging point 81a of axially adjacent and angularly spaced follower 81 (FIG. 3) engages an associated cylindrical cam track 75 ofthe same cam member and is actuated thereby.

Followers 81 and `83 are pivotally arranged on each of the shafts 85 and 86 in essentially the same manner. However, axially adjacent cam followers 81 `and 83 on the shaft 85 (FIG. 3) are controlled by the cylindrical cam tracks 75 and 77 respectively of one of the cam members 69, and another pair of axially adjacent followers v8.1 and 83 which vare diametrically disposed on :shaft 86 at the other side of the cam stack are controlled by the appropriate cylindrical cam tracks of the next cam member, etc. This arrangement of the yfollowers enhances the smfallness lin size of the controller 1 for providing a multiplicity of controlling functions.

To operate a multiplicity of electri-c switches in response to pivotal movements of followers 81 and `S3, as illustrated in FIG. 3, `each of the terminal boards 17 and 18 provides two tiers of :single pole single throw switches 87. Each of these switches 87 is normally closed and includes a pair of fixed and movable contacts 89 and 91 respectively, the movable contact 91 being supported by an elongated blade 93. 93 is Idisposed alongside of and next to a switch actuating Each of the movable contact blade-s point 811.1 or -83c of one of the followers 81 or 83. The followers 81 and y83 are pivotally arranged upon their bearing shafts 85 and 86 so that the cam engaging points 81a and 83a may ride upon :cylindrical tracks 75 and 77 of the cam members 69, and switch actuating points .81C

and 83C are in engagement with associated movable contact blades 93 (FIG. 3). It will thus be seen (as shown in FIGS, 2 and 3) that the controller 1 .includes four groups of angularly aligned followers which .are time driven to control adjacent associated switches.

To bias each of the movable contact blades to its. normally closed position, compression springs 94 (FIG. `3) are utilized. The springs 94 run in. compression between wells formed in the terminal boards, .and the blades 93, to bias movable contacts 91 into engagement with their associated xed contacts 89. The biasing force provided for each blade 93 is thereby exerted by the blades upon points 81al and `83a` of the followers, to bias the followers radially (about their axes) toward the axis of the cam. members 69. (See FIG. 3.) When the cam engaging point of each follower (e.g., point 81a of follower 81 in FIG. 3) is :at its radially innermost position with respect to its associated cam track, the switch operated by this follower then remains in its normally closed position. As the associated cam member 69 is thereafter rotated intermittently by the previously described drive mechanism, when the cam engaging point reaches the radially outermost position of lits cam track, the follower -is cammed radially outwardly (relative to cam member 69) to overcome the biasing force of its .associated movable contact blade 93 and it opens the associated fsw-itch.

For enhancing the control flexibility for the followers of sequence controller 1, as shown in FIG. 3, an :auxiliary cam stack 96 has been utilized. The cam stack 96 includes a shaft 96a, auxiliary cam gear 96h fastened to shaft 96a, and .one or more auxiliary cams 96C suitably fastened to cam gear 96b. Cam gear 96h is in mesh with gear 40 (FIG. 2) and thereby driven through drive mechanism 5. The auxiliary cam 96C is adjacent to and engageable with an inwardly extending shoulder 81d or 83d of 'an associated cam follower S1 or `83. Thus, gear 40 drives -auxiliary cam gear 96b to operate a switch 87 adjacent to an associated cam follower. (See FIG. 3.) More particularly, when the radially innermost surface of cam 96e is .adjacent shoulder 81d or `83d of the follower `81 or 83, it has no yeffect thereupon. However, in response to time driven rotation of auxiliary cam gear 96h, when the radially outermost surface of cam 96h is reached, follower 81 or 83 is actuated by auxiliary cam '96s, `and the associated movable contact .blade 93 is cammed to its contacts r open position (FIG. 3).

Turning now t-o an important aspect of the present invention, as shown in FIGS. 1, 4, and 5, we have provided an improved means Afor manually controlling la main switch of controller 1 and also setting the main cam stack. For an understanding of this arrangement, attention is first ldi-rected to cam shaft 73j. The shaft 73 is rotatably journalled .at its front end through :a suitable aperture in front plate 13 (not shown). The other or back end 95 of shaft 73 is keyed to ratchet wheel 65 for rotation with .switch operating unit `6. More particularly, near the back end 95 of shaft 73, there is a cylindrical keying projec- .tion 97 which extends radially outwardly from the periphery of shaft 73, :as shown in FIG. 4. The ratchet wheel 65 is journalled to back plate 15 by means of an integralcylindrical bushing 99 which is extended through an aperture 100 in plate 15. In particular, as shown in FIGS. 4 and 5, bushing 99 of the ratchet wheel is rotatably Y .supported in aperture 100 of plate 15 and retained in axial y relationship with the aperture V100 by means of a C-shaped clip 101 which enters an annular groove yformed in this bushing 99. The rotatable bushing 99 o-f ratchet wheel 65 has `an aperture i103 (FIG. 5) through which the back l end 95 of the camshaft 73 is extended, and a keyhole slot 105 which extends radially outwardly from aperture 103 for receiving the keying projection 97 of the shaft 73. By means of cooperation between the keying projection 97 of cam sha-ft 73 .and the keyhole slot 105 of the bushing 99 of ratchet wheel 65, as is well known in the art, the ratchet wheel 65 .and the cam shaft 73 are locked together for conjoint rotative movement, while the shaft 73 is free to reciprocate relative to the ratchet wheel 65.

To manually .actuate a master switch of the controller 1 by axial motion or -reciprocation of cam shaft 73, a frusto-conioal surface 107 (FIG. 5) is formed near back end of the shaft 73. Surface 107 has its smallest diameter closest to end 95 of the shaft, and coacts with a V-shaped curved notch 109 of .an actuating assembly to cam open the contacts of the master lswitch 87a when the cam shaft is depressed. More particularly, the notch 109 is formed within one end of an elongated aperture 1x1-1 of channel-shaped member 113 (FIGS. 4 and 5). Member 113 has its flat bight section 115 (wherein the aperture 111 is formed) rigidly connected to a narrow slot 117 (FIG. 5) of an L-shaped actuator 121.

The actuator 121, as shown in FIGS. 1, 4, and 5, comprises an elongated section 119 wherein the aforementioned slot =117 is formed, a shorter section 12.3 disposed with its longitudinal axis generally parallel to cam shaft 73 and perpendicular to the axis of section 119, and shoulder 1215 which extends outwardly from elongated section 119, as an extension thereof (FIGS. 4 and 5). The shorter section 12.3 of the actuator 121 extends inwardly through an enlarged slot 127 (FIG. l) in the back plate 15, being in perpendicular disposition thereto. Section 123 engages an associated cam follower 83 to operate the main control switch 87a, as shall become apparent hereinafter.

The frusto-conical surface 107 of shaft 73 and the channel-shaped member 113 are generally disposed at the rear of controller 1, between back plate 15 and support plate 3l). In viewing FIG. l, it will be noted that the longitudinal axis of the actuator assembly (i.e., the axis described by the bight section of member 113 and section 119 of actuator 121) is disposed at approximately 45 to the longitudinal axis of blade 93 of the master control switch 87a. Such an arrangement is important in obtaining efficient space utilization in the controller 11. For effectively controlling the movement of actuator 121 with relation to its associated switch 87a, on shoulder 125 of the actuator, there is formed a curved apex 129 and a flattened side 129a connected thereto. The flattened side 129e of actuator `1121 rides transversely along an adjacent curved surface 131a of a flag-shaped tab 131 of the back plate 1'5 (FIG. l) and is skewed thereby so that section 123 of the actuator moves in a direction generally perpendicular t0 blade 93. Thus, tab 131 extends perpendicularly outwardly from plate 15, on the left side of slot 127 (viewing FIG. l) and acts upon side 129a of the actuator 12.1 to redirect the motion of its actuating section 123 from a 45 relationship with blade 93 to approximately a 90 relationship with blade 93 (FIG. l).

For biasing the actuating assembly v113, 121 to its normal operating position relative to cam shaft 72 (i.e., when shaft 73 is in its on or undepressed position), we have provided a leaf spring 133. (See FIG. 4.) Spring 133 has one of its ends 134 bent over and suitably fastened to a supporting stud projecting outwardly from back plate 15. The free end 136 of spring 133 engages a flattened side 135 of the shoulder 125 to bias the actuator assembly 1.13, 121 diagonally and upwardly to the right along tab 131, viewing FIG. l. As previously mentioned, shaft 35 extends outwardly from back plate 15 toward support plate 30. Shaft 85 engages the underside of spring 133 between its ends (FIG. 1) and stresses the free end 136 of the spring upwardly (FIG. 1) so that it imparts a compressive action to flattened side 13.5 of

the actuator assembly 113, 121. It will thus be seen that spring 133 provides a simpliiied means for continuaoeaaos ously urging the actuator assembly 113, 121 to ride inwardly or away from the spring 133 along tab 131 and thereby biases this assembly to the position wherein it is shown in FIG. 4.

-For an explanation of the operation of the master control switch `37a in our improved controller, attention is now directed to FIGS. 4- and 5. In FIG. 4, shaft 73 is illustrated in its outermost or undepressed position (relative to the front of controller 1). The inner corner of actuator notch 11i@ is then in engagement with the cylindrical surface at the extreme end 95 of shaft 73 and the actuator assembly 113, 121 is biased to this position by spring 133. With the shaft 73 in this position, actuating surface 123e of the shorter section 123 of actuator 121 has no eifect upon the follower 33 which controls master switch 87a, and this switch 37a is in its normally closed position. When cam shaft 73 is pushed downwardly and diagonally to the right from where it is shown in FIG. 4 (i.e., when bottom end 95 moves away from back plate 15), the V-shaped notch 169 of actuator channel member 113 is engaged by frustoconical cam surface 1117 of shaft 73 and actuator assembly 113, 1211 is thereby moved diagonally toward the curved bottom 131a of flag-shaped tab 131 (FIG. 1). Flattened surface 12911 of the actuator rides along tab 131 against the force of spring 133 in a generally perpendicular direction, or downward toward side 139 (viewing FG. 1) of back plate 15. As the actuator assembly 113, 121 moves transversely in response to the eamming effect thereupon of shaft 73, the assembly is guided for transverse movement between plates 15 and 31B.

When shaft 73 reaches its depressed position (which is represented in FIG. 5), the surface 123a (FIG. 4) of the actuator assembly 113, 121 has been skewed by tab 131 into a generally perpendicular direction toward blade 93 of the switch and this surface has acted upon follower 83 to open the master switch 87a. It will be understood that master switch 67a is electrically connected to timing motor 3 so that when shaft 73 is depressed, this motor is thereby deenergized. It will be further understood that when shaft 73 is pulled outwardly from its depressed position, a reverse operation of actuator assembly 113, 121 ensues, and spring 133 takes over to close the master switch 87a.

When viewing FIGS. 4 and 5, it will be noted that master switch 87a of controller 1 is operable by the follower S3. This particular follower 63 is the same type of follower as the other followers 83 (FIG. 3) and, as shown in FIG. 5, it is likewise also operable by one of the cam members 69.

It will now therefore be seen that by means of the frusto-conical cam surface 107 formed upon shaft 73 and the structure and mode of operation of actuator assembly 1113, 121, the mai-n controlling switch 87a of our sequence controller 1 may be readily operated manually to control a driving means for the controller, such as timing motor 3. With this arrangement, motor 3 may be simply and efliciently turned off before advancing the cam stack to its desired starting position.

Turning now to another and very important aspect of our invention, attention is further directed to FIGS. 1, 4, and 5. On the shaft 86 near to side 140 (FIG. l) of back plate 15 and between the back plate 15 and support plate 3i) (FIG. 2), there is pivotally mounted a spring biased lever 141. The lever 141 essentially comprises a flat body section 143 with an elongated aperture 145 formed therein, latching arm 147 with a stop tooth 149 formed thereon, operating arm 151 with a shoulder i153 formed thereon, and biasing arm 155 with a notch 157 formed therein. The arm 147 is parallel to the flat body section 143 and spaced slightly inwardly therefrom toward ratchet wheel '65 by connecting portion 'i159 (FIGS. 4 and 5). Shoulder 153 is directed perpendicularly outwardly from the plane of body section 143 of the lever toward support plate 311 (FIG. V2). Biasing arm 155 is directed an- 8 gularly inwardly and away from body section 143` of the lever, in the same general direction as connecting portion 159, as shown in FIGS. 4 and 5.

The lever 1411 is pivotally mounted upon `shaft 86, as shown in FIGS. 4 `and 5, by slipping the elongated aperture 145 of lever 141 around the end 86a of shaft `86. A C-shaped clip l161 is tted into an annular groove (not shown) `formed at the outer end of shaft S6 to retain body section 1413 of the lever in parallel disposition to :back plate 15, between plate 15 and support plate 30. (See FIG. 2.) As shown in FIG. f1, a slot 163 is formed in plate 15 adjacent arm `147 of lever 141, and a slot 165 is formed in plate 15 adjacent the biasing arm 155 of the lever 141. The connecting portion 159 near arrn 147 extends inwardly through the slot i163, and biasing arm extends inwardly through the slot 165. (See also FIG. 2.)

To enable lever 1451 to act upon the rotatable switch operating unit 6 and precisely locate the beginning of a program or part thereof for controller 1, outermost face 164 of ratchet wheel 65 has an annular recess 1166 with a stop notch 169 formed therein. More specifically, recess `166 is formed in wheel 65 between a generally cylindrical inwardly facing rim 167, and `a hub portion (not shown) behind bushing 99 (FIG. 4). Stop notch 169 is formed as an interruption of rim 167, and is sufliciently wide to allow tooth 149 of rlever 1411 to enter it. (See FIG. 5.) Upon depression and rotation of cam shaft 731, the lever 141 is spring biased radially outwardly against rim 167 of ratchet Wheel 65 so that when the tooth i149 enters notch 169, it engages the notch and the switch operating unit 6 is retained in a predetermined starting position.

For continually biasing stop tooth '149 of lever i141 into engagement with notch 169', the .previously mentioned coil spring 61 (FIGS. 4 and 5) runs in tension between motch 157 of the biasing arm `155 of lever 1141, and notched arm k57 of `driving pawl 55. By using spring 61 in this manner, it has been found unnecessary to use separate springs for biasing the lever 141 and pawl 55 in accordance with their respective functions. A resultant cost reduction is therebyachieved by the use of the spring 61.

For a detailed explanation of the operation of lever 141, attention is now ydirected to FIG. 4. When cam shaft 73 is in its outermost or undepressed position (FIG. 4), end I171 of the channel-shaped member 113 engages side 153e of lever shoulder 15?. The force of leaf spring "133 thus holds end `171 of actuator assembly 1113, 121 against shoulder 153 of lever `141 tin opposition to the biasing yforce imparted to lever l1411 by spring 61. The result of this condition is that stop tooth i149 of the lever -141 is held radially inwardly (toward the axis of wheel `65) and away from the inner rim 167 of the ratchet wheel 65. IIn other Words, the action of actuator assembly 113, 121 upon operating arm i151 of lever 141 partially overcomes the biasing force imparted to arm 155 of lever 141 by spring 61, to hold lever 141 in the position where it is shown in FIG. 4, with stop tooth 1149 out of engagement with rim 167. With lever 141 in this position, shaft 86 is on the left side of elongated slot 1415 (viewing FIG. 4).

However, when the cam shaft 73 is depressed or moved to its innermost position for opening the line switch 87a, the frusto-conical surface 107 of shaft 73` acts upon notch 1019 of the member 113 to force the end 171 of the actuator assembly away from shoulder 153- of the lever i141. As end i171 of the actuator lassembly moves away from shoulder 153 of lever 141 (toward the position where it is shown in FIG. 5), the spring I61 takes over and forces tooth 149 to pivot into engagement with rim Ii167. With the cam shaft 73 depressed, as the main switch operating unit 6 is then rotated in a counterclock wise direction (viewing FIG. 5), the ystop tooth 149 of lever 141 rides upon rim 167 until it reaches the positive stop notch y169. `Once tooth 149 of lever 141 has entered notch '169, further rotation of the switch operating unit 6 in the same `direction causes shoulder l149a of the tooth 149 to reach side shoulder 16911 (FIG. 4) of the notch v169 and also pulls lever 141 against the force of spring 61 until the right side of elongated slot 145 engages shaft 86 (as shown in FIG. 5). When this action has occurred, the operating unit 6 is stopped at a `desired predetermined starting position for the sequence controller 1.

When the cam sha-ft 73 has been depressed to open the line switch 87a and the switch operating -unit 6 has been thereafter rotated until the unit 6 has reached its predetermined starting position (FIG. pulling shaft 73 outwardly (to turn on the controller 1) causes lever 1-41 to pivot on shaft 86 so that stop tooth 149 moves out of notch 169. More particularly, actuator assembly 113, l121 return to its position shown in FIG. 4, where it engages shoulder '153 of lever 141. The force of spring 611 is thus partially overcome to pivot tooth 149 of lever 141 out of engagement with notch 169. As the tooth 149 clears the stop notch 169, spring 61 pulls the elongated aperture 145 of lever 141 from the position Where it is shown in FIG. 5 to a position similar to that shown in FIG. 4. Shaft 86 is then again on the left side orf elongated aperture 145 (as shown in FIG. 4) and tooth '149 of lever 141 is pulled laterally away from notch 169 so that it now abuts rim 167 at a point represented by dotted lines in FIG. 5. With such an arrangement, tooth 149 cannot re-enter notch 169 after shaft 73 is pulled out and then immediately depressed. Under such condition, due to the arrangement of the elongated aperture 145 of lever `141 on shaft 86, the unit 6 must be rotated another revolution before the unit 6 may again be positively stopped in the starting position.

lt will thus be seen that by means of spring biased lever 141 and the cooperation between tooth 149 thereof and the stopping notch 169, a simplied and precise starting position for the commencement of a program (or part thereof) by the sequence controller 1 is thereby achieved.

From the foregoing, it will now be understood that there is provided an improved sequence controller with a novel and ellicient actuating means for -manually operating one of the electric switches. It will further be seen that the improved sequence controller 1 includes an effective positive positioning means which is controllable by the manually operatble -actuating means for assuring that the sequence controller will start in a predetermined location.

While in accordance with the patent statutes, we have described what at present is considered to be the preferred embodiment of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing lfrom the invention, and we, therefore, aim in the Afollowing claims to cover all such equivalent variations that fall within the true spirit and scope of this invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In a timing mechanism including a plurality of sequentially operable control devices, a rotatable operating unit for actuating said devices, a shaft coaxially arranged within said unit for setting said unit, said shaft being disposed for reciprocable movement relative to said unit, a camming surface on said shaft, an actuator having a follower surface thereon, a control element arranged for operation by said actuator, said camming surface on said shaft being disposed for coaction with said follower lsurface on said actuator to move said actuator transversely relative to the axis of said shaft in response to reciprocation of said shaft for operating said control element, `and a positive stop means including said actuator arranged to coact with said rotatable unit for positioning said unit at a predetermined programming position.

2. In a timing mechanism including a plurality of sequentially operable control devices, a rotatable operating unit for actuating said devices, a shaft coaxially arranged within said unit for setting said unit, said shaft being disposed for reciprooable movement relative to said unit, a camming surface on said shaft, an actuator having a follower surface thereon, a control element arranged for operation by said actuator, said camming surface of said shaft being disposed for coaction with said follower surface of -said actuator to move said actuator transversely relative to the axis of said shaft in response to reciprocation of said shaft for operating said control element, and a positive stop means arranged for activation by said actuator in response to reciproeation of said shaft to coact with said rotatable unit for positioning said unit at a predetermined starting position.

3. Control mechanism comprising -a plurality of switches, a rotatable operating unit for actuating said switches, means for driving said unit through -a timed cycle of operation, =a manually operable switch, `a shaft extending coaxially through said unit and linked thereto for setting said unit by rotation of said shaft, said shaft being reciprocably movable between rst and second positions relative to said unit, a camming surface formed on said shaft, an actuator with a follower surface formed thereon, said camming surface of said shaft being disposed for coaction with said follower surface of said actuator to move said actuator transversely relative to the Iaxis of said shaft in response to axial movement of said shaft from said first to said second position thereby to open said manually operable switch, a positive indexing means formed in said rotatable operating unit, and a pivoted latching lever arranged for lactivation by said actuator when said shaft is in said second position, said latching lever being engageable with said positive indexing means upon rotation of said shaft in the second position for positively positioning said unit at a predetermined starting position.

4. The control mechanism of claim 3 wherein the latching lever has an elongated aperture formed therein, a pin extended through said aperture for pivotally supporting said latching lever, said lever being in slidably cooperating disposition with said pin and arranged thereupon so that when said lever is in engagement with said positive indexing means and said shaft is moved from said second vto said first position the lever slides on said pin to prevent re-engagement of said lever with said indexing means until Said unit is substantially rotated relative to said lever.

5. Control mechanism comprising a plurality of switches, a `rotatable operating unit for actuating said switches, one of said switches including an elongated movable contact blade, `a shaft extending coaxially through said unit and linked thereto for setting said unit by rotation of said shaft, said shaft being reciprocably movable between first and second positions relative to said unit, :a camming surface on said shaft, an actuator located near one end of said shaft, said actuator having an elongated section disposed transversely to the axis of said shaft and at an acute angle relative to the longitudinal axis of the movable blade of said one switch, -a follower surface on `said elongated section, said camming surface of Isaid shaft being disposed for coaction with said follower surface of said actuator to move said actuator transversely relative to the axis of said shaft in response to axial movement of said shaft from said first to said second position thereby to open said one switch, skewing means for controlling the transverse movement of said actuator so that said actuator directs an actuating force in perpendicular disposition to the axis of said movable blade, a positive indexing means formed in said rotatable operating unit, and a pivoted latching lever arranged for activation by said actuator when said shaft is in said second position, said latching lever being engageable with said positive indexing means upon rotation of said shaft in the second position for posiaccesos l 1 tively positioning said unit at a predetermined starting position.

6. `Control mechanism comprising Ia plurality of switches, a rotatable operating unit for actuating said switches, one of said switches including an elongated movable contact blade, a shaft extending coaxially through lsaid unit and linked thereto for setting said unit by rotation of said shaft, said shaft being reciprocably movable between first and second positions relative to said unit, a camming surface on said shaft, an actuator located near one end ofsaid shaft, said actuator having an elongated section disposed transversely to the axis of said shaft and at an iacute angle relative to the longitudinal axis of the movable blade of said one switch, a follower surface on said elongated section, said camming surface of said shaft being disposed for coaction with said follower surface of said actuator to move said actuator transversely relative to the axis of said shaft in response to axial movement of said shaft from said first to said second position thereby to open said one switch, and skewing means for controlling the transverse movement of said actuator so that said actuator directs an actuating force in generally perpendicular disposition to the axis of said movable blade.

7. Control mechanism comprising a plurality of switches, a rotatable operating unit for actuating said switches, means operable by one of said switches for driving said unit through a timed cycle of oper-ation, a shaft extending coaxially through said unit and linked thereto for setting said unit by rotation of said shaft, said shaft being reciprocably movable between first and second positions relative to said unit, a camming surface formed on said shaft, said camming surface having a frusto-conical configuration, an `actuator with la follower surface formed thereon, said follower surf-ace having a generally V-shaped configuration, said camming surface of said shaft being disposed for coaction with said follower surface of said actuator to move said actuator transversely relative to the `axis of said shaft in response to `axial movement of said shaft from said first to said second position thereby to open ysaid one switch and deenergize the driving means for said unit, a positive indexing means formed in said rotatable operating unit, and a pivoted latching lever arranged for activation by said actuator when said shaft is in said second position, said latching lever `being engageable with -said positive indexing means upon rotation of said shaft in the second position for positively positioning said unit at a preedtermined starting position.

8. Control mechanism comprising a plurality of switches, a rotatable operating unit for actuating said switches, means operable by one of said switches for driving said un-it through a timed cycle of operation, `a shaft` extending coaxially through said unit and linked thereto for setting said unit by rotation of said shaft, said shaft Ibeing reciprocably movable -between first `and second positions relative to said unit, a camming surface formed on said shaft, an actuator with a follower surface formed thereon, said camming surface of said shaft being disposed for coaction with said follower surface of said actuator to move said actuator transversely relative to the axis of said shaft in response to axial movement of said shaft from said first to said second position thereby to open said one switch and deenergize the driving means of said unit, an indexing notch formed in said rotatable operating unit at one end thereof, a pivoted latching lever engaging said actuator when said shaft is in said first position and arranged for lactivation by said actuator when said shaft is in said second position, spring biasing means for normally urging sa-id latching lever into engagement with said indexing notch, said lever being moved by said biasing means into engagement with said notch upon rotation of .said shaft in the second position for positively positioning said unit at a predetermined starting position.

9. Control mechanism comprising a plurality of switches, a rotatable operating unit for actuating said switches, means for driving said unit through a timed cycle of operation, said means including a ratchet wheel associated with said unit `and a driving pawl intermittently engageable with said wheel for driving said unit, a manually operable switch, -a shaft extending coaxially through said unit and linked thereto for setting said unit by rotation of said shaft, said shaft being reciprocably movable between first and second positions relative to said unit, a camming surface formed on said shaft, Ian actuator with a follower surface formed t-hereon, said camming surface of said shaft being disposed for coaction with said follower surface of said actuator to move said `actuator transversely relative to the axis of said shaft in response to 'axial movement of said shaft from said first to said second position thereby to open said lm'anually operable switch, a positive indexing means formed in said rotatable operating unit, a pivoted latching lever `arranged for activation by .said actuator when said shaft is in said second position, a biasing spring arranged in tension between said driving pawl and said latching lever to urge said pawl into engagement with said ratchet wheel and to concurrently urge said lever into engagement with said indexing means, said latching lever 'being engageable with said positive indexing means upon rotation of said shaft in the second position for positively positioning said unit at a predetermined starting position.

l0. The control mechanism of claim 9 wherein the actuator is L-shapedin configuration, said actuator comprising an elongated section with an ,aperture formed therein between first and second ends` of said section, said aperture having a follower surface of V-shapcd configuration formed thereon, said shaft extending through said aperture `and having a frusto-conical camming surface formed thereon, said frusto-concal surface coasting with the follower 4surface of the actuator to move said actuator transversely tothe axis of the shaft between first and second positions in response to reciprocation of said shaft, said first end of said actuator section having a control surface thereon for deflecting the transverse movement of said actuator from one direction to another direction for controlling said manually operable switch, said second end of said actuator section being engaged with said lever to preclude engagement of said latching lever with said indexing means when said `shaft is in said first position.

References Cited in the file of this patent UNITED STATES PATENTS 2,066,246 Bolton Dec. 29, 1936 2,297,694 Dunham Oct. 6, 1942 2,300,020 Smith Oct. 27, 1942 2,311,545 Hurley et al. Feb. 16, 1943 2,585,018 Kreitchman et al Feb. l2, 1952 

1. IN A TIMING MECHANISM INCLUDING A PLURALITY OF SEQUENTIALLY OPERABLE CONTROL DEVICES, A ROTATABLE OPERATING UNIT FOR ACTUATING SAID DEVICES, A SHAFT COAXIALLY ARRANGED WITHIN SAID UNIT FOR SETTING SAID UNIT, SAID SHAFT BEING DISPOSED FOR RECIPROCABLE MOVEMENT RELATIVE TO SAID UNIT, A CAMMING SURFACE ON SAID SHAFT, AN ACTUATOR HAVING A FOLLOWER SURFACE THEREON, A CONTROL ELEMENT ARRANGED FOR OPERATION BY SAID ACTUATOR, SAID CAMMING SURFACE ON SAID SHAFT BEING DISPOSED FOR COACTION WITH SAID FOLLOWER SURFACE ON SAID ACTUATOR TO MOVE SAID ACTUATOR TRANSVERSELY RELATIVE TO THE AXIS OF SAID SHAFT IN RESPONSE TO RECIPROCATION OF SAID SHAFT FOR OPERATING SAID CONTROL ELEMENT, AND A POSITIVE STOP MEANS INCLUDING SAID ACTUATOR ARRANGED TO COACT WITH SAID ROTATABLE UNIT FOR POSITIONING SAID UNIT AT A PREDETERMINED PROGRAMMING POSITION. 